Convenience outlet having lanced contact strips



Nov. 8, 1955 G. B. BENANDER CONVENIENCE OUTLET HAVING LANCED CONTACT STRIPS Filed Oct. 16. 1953 3 m 3 w n Z Z 0 W2 0 why 60 in vent or:

George Benan Hi6 Attor' United States Patent P 2,723,385 CONVENIENCE OUTLET HAVING LANCE!) CONTACT STRIPS George B. Benander, Oaklawn, R. I.,. assignor to General Electric Company, a corporation of New York Application October 16,. 1953,. Serial No. 386,558

2 Claims. (Cl. 339-263) The present invention relates to a convenience outlet for electric wiring. systems such as are used for connection with one or more attachment plugs.

The object of my invention is to provide an improved construction of a convenience outlet which is safe in operation and which may be produced at comparatively low cost.

A further object of my invention is to provide improved terminal screw means in a convenience outlet such that the outlet may be wired from the back.

According to my invention, contact strips mounted in a suitable insulating housing are provided centrally thereof with bent-over portions which face each other, and a terminal screw is threaded into an aperture between said portions. The bared ends of the power supply wires may then be inserted through suitably positioned openings in the back of the outlet and under said bent-over portions which are thereafter forced into clamping engagement with the wires by the head of the terminal screw as it is screwed into place.

The back-wiring feature of my invention eliminates the necessity of looping the wires around the terminal screws when the outlet is installed. While outlets which can be back-wired have heretofore been available on the market, my invention makes it possible, by means of the bentover tabs on the contacts, to eliminate one terminal screw in each contact so that, since the remaining terminal screw is here not a current-carrying element, it can be made from a ferrous material which contributes to a minimum cost. The use of the benttabs also eliminates a clamping member which usually is mounted on each terminal screw of the outlets having. a back-wiring feature which are now on the market.

My invention will be better understood from. the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the drawing:

Fig. l is a plan view of a duplex outlet embodying the invention.

Fig. 2 is a side elevational view of the duplex outlet of Fig. 1, showing a wire connected thereto.

Fig. 3 is a partially exploded, isometric view of the parts which are included in my outlet.

Referring in detail to the drawing, the outlet embodying the invention comprises a recessed body member which may be made of molded phenolic or other suitable insulating material. The body member 10 has a front wall 11 provided with two pairs of spaced slots 12 and 13 in outwardly extending bosses 14 and 15 for guiding and receiving the prongs of attachment plugs to be connected to the outlet. The back of the body member 10, as best shown in Fig. 3, is formed with pairs of spaced recesses 16 and 17 in alignment with the aforementioned slots 12 and 13 respectively.

Similar spring contacts 18 and 19 are each arranged within the body member to be supported in recesses 16 and 17 along opposite outer walls of the body 10, as is shown will be understood by one skilled in the art.

Patented Nov. 8, 1955 in Fig. 3. These spring contacts are separated from each other by a pair of transversely spaced, longitudinally extending partitions 20 and 21.

On the outer side walls of both recesses 16 and 17 are formed internally projecting buttresses 22 and 23 respectively. In addition, on the outer wall of each longitudinal partition 20 and 21 are formed a pair of buttresses 24 and 25 which are located between the aforementioned buttresses 22 and 23. The buttresses 22, '23, 24 and 25 serve to support the spring contacts-in an upright position in the recesses 16 and 17.

The spring contacts 18 and 19 are identical; therefore, I will describe only one of them. The spring contact 19 is made from a thin, flat, elongated strip of spring copper which has a deformed center portion 55 as is seen in Fig. 3 and corner portions 26 at each of the four corners of the contact which are slightly bent over to provide an inclined surface to facilitate the easy insertion of the prongs of an attachment plug (not shown) into good electrical. contact with the spaced ends of the contacts 18 and 19, as It will be understood that only the bent ends 26 of the contact which are immediately under the front wall of the outlet are engageable with the prongs of an attachment plug, The reason for making the four corners of the contact alike is that thereby a single design of contact can be used on both sides of. the convenience out-let, thus reducingthe cost of the contact elements.

Tongues 27 and 2S are'preferably struck out of the central deformed portion of the contact and bent back on themselves so that the ends of the tongues are facing each other. Between the tongues there is formed a threaded aperture 29 which is adapted to receive the terminal screw 30, preferably made of ferrous metal.

The side walls of. the body 10 are provided witha square shaped opening 31 which exposes to view the said tongues 27 and 28 and the terminal screw 30 when the contact is positioned within the body 10. Looking at Figure 2 of the drawing, it is clear that the reversely curved portions of the tongues 27 and 28 are closely fitted between the opposed side walls of the opening 31. Thus, when the terminal screw 30 is tightened down the side walls of the opening 30 prevent the tongues 27 and 28 from spreading outwardly away from the screw. This feature serves to ensure a more positive connection between the tongues and the lead wires so as to successfully pass the rigid pull tests made by the Underwriters Laboratories.

The back of the body of the outlet is closed by the fiber insulating plate 32 which isheld in place by a yoke or supporting strap 33. The insulating plate 32 is provided with a pair of small apertures 53 and 54 formed at each longitudinal side of the plate 32 in alignment with the tongues 27 and 23 so that the fully assembled outlets may be wired from the back.

The supporting. strap isgenerally of U-shape with end portions 34 and 35 having openings. 3&3 to facilitate connection with corresponding portions, or ears, of an outlet box. The central portion of the strap 33 has an arm or member 37 preferably lanced out of the strap by a punching operation and bent forward toward the front of the body 10. When assembled, the lanced member 37 projects through an elongated slot 38 in the insulating plate 32. Portions 39 are cut out of the ends of the insulating plate 32 to form spaced projections 40 and 41 which straddle the legs 42 and 43 of the U-shaped portion of the strap 33 to assist in holding the parts in a fixed position. The lanced member 37 is positioned in the body 10 in the close-fitting grooves 44 and 45 which extend to the front wall of the body. Also formed in the front wall of the body member is an elongated slot or aperture 46 which communicates with the said grooves 44 and 45 for a reason which will be explained later. After assembly,

the free-end portion 47 of the lanced member 37 is bent at right angles to the main portion of the member so that it covers the aperture 46, as is seen in Fig. 1, and also overlies a portion of the front face of the outlet. This arrangement confines the body and the insulating plate 32 between the bottom wall of the U-shaped portion of the mounting strap 33 and the bent-over end 47 of the lanced member 37.

The free end of the lanced member 37 has also a threaded opening 48 which overlies the aperture 46 in the center of the front face of the outlet. This opening 48 is provided so as to receive a screw means (not shown) which supports a face plate (not shown) on the outer face of the outlet, as is well known in the art.

The legs 42 and 43 of the U-shaped portion of the mounting strap 33 are designed to be located within the spaced grooves 49 and 50 at each end of the body member of the outlet. There are narrow curved portions 51 and 52 formed as part of the strap 33 which join the elements 34 and 42, and 35 and 43 respectively so that the end portions 34 and 35 of the strap may extend outwardly from the body member.

I have filed a copending application, Serial No. 386,557, filed October 16, 1953, now Patent No. 2,695,392, which claims the supporting strap arrangement for connecting and holding the insulating plate and body member together. The invention which is claimed herein resides in the construction embodying the contact strips 18 and 19 and arrangement by which these elements are to be connected to the power supply wires.

In order to wire an outlet which contains my invention, the bared end of a wire 56 is inserted into one of the apertures 53 or 54 in the back of the outlet and under one of the cooperating bent tongues 27 or 28 which are formed on the contacts 18 and 19. A clamping connection between the tongues on the center portion 55 of the contact and the wires is provided by the central terminal screw 30 which is arranged to engage the free ends of the tongues 27 and 28 so as to press them firmly down and against the underlying wires. This possibility of wiring an outlet from the back eliminates the necessity of looping the conductors around the terminal screws. By my invention, it is possible to eliminate one terminal screw in each contact While still providing for the connection of two wires to each contact; also no threaded clamp members or similar elements are required as were heretofore necessary. In addition, since the terminal screw 30 is not a current-carrying member, it may be made of a ferrous material and still meet the Underwriters specifications, which contributes to a minimum cost.

Consequently, having described my invention of an improved convenience outlet and novel means for connecting electrical conductors to its contacts, it will be readily apparent to those skilled in the art of manufacturing and installing electrical wiring components that I have provided an outlet with a minimum number of parts, which is simple in design and easy to manufacture, as well as easy to assemble with a minimum amount of hand labor. At the same time, I have provided an outlet with a backwiring feature which, heretofore, has been found only on premium-priced outlets because of the relatively high cost of providing such a feature.

It will be understood that this invention can be applied to other designs of outlet housing construction; for example, a different assemblying and fastening means from that illustrated can be used. Similarly, the specific arrangement for supporting the contact strips in the insulating housing can be varied, and the relative positions of body and cover can be changed as desired.

Other modifications of this invention will occur to those skilled in the art. It is to be understood, therefore, that this invention is not limited to the particular embodiment disclosed, but that it is intended to cover all modifications which are within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a wiring device for electric wiring systems comprising an insulating body member, an insulating cover member, contact members positioned in said body member, each contact member having at least one lanced tongue bent in a reverse curve which has an end portion raised from the surface of the contact, and an adjustable screw means for forcing said tongue down onto the said surface of the contact, and apertures in the back wall of the device so that a conductor may be inserted therethrough and under the said tongues on said contacts to be clamped thereunder by the said screw means, and abutment means formed on said body member adjacent the bight of each tongue to limit the movement of the tongues away from the screw means due to the clamping action thereof.

2. In a wiring device for electric wiring systems comprising an insulating body member, and insulating cover member, contact members positioned in said body member, each contact member having a pair of lanced tongues which are bent in a reverse curve so that they face each other, each tongue having an end portion raised from the surface of its supporting contact, and an adjustable screw means for each contact located between the pair of tongues for forcing said tongues onto the said surface of the contact, and apertures in the back wall of the device so that a conductor may be inserted therethrough and under the said tongues on said contacts to be clamped thereunder by the said screw means, the adjustable screw means and the adjacent tongues of each contact being exposed to view by a window formed in both of the sides of the device, the portions of said windows adjacent the bight of each tongue serving to limit the movement of the tongues away from the said screw means under the clamping action thereof.

References Cited in the file of this patent UNITED STATES PATENTS 839,346 Wardman Dec. 25, 1906 1,942,341 Mangin Jan. 2, 1934 2,109,073 Nieman Feb. 22, 1938 2,216,740 Hubbell Oct. 8, 1940 2,326,538 Hutt Aug. 10, 1943 2,684,994 Kwake July 27, 1954 

